TCA6408A/TCA6408-Q1 I2C & SMBus I/O Expander Texas Instruments TCA6408A/TCA6408-Q1 I2C & SMBus I/O Expander provides 8-bits of general-purpose parallel input/output (I/O) expansion. This can be done for two-line bidirectional I2C bus or SMBus protocol. These can operate with a power supply voltage ranging from 1.65V to 5.5V. This is done on both the I2C bus side (VCCI) and on the P-port side (VCCP). The TCA6408A can interface with next-generation microprocessors and microcontrollers on the SDA/SCL side, where supply levels are dropping down to conserve power. In contrast to the dropping power supplies of microprocessors and microcontrollers, some PCB components such as LEDs, remain at a 5V power supply. The device supports both 100kHz (Standard mode) and 400kHz (Fast-mode) clock frequencies. The TCA6408A provides a simple solution when additional I/Os are needed for switches, sensors, pushbuttons, LEDs, fans, and so forth. The TCA6408-Q1 devices are AEC-Q100 qualified for automotive applications.